Oxidation of hydrocarbons and waxes



Patented Nov. 20, 1934 1,981,384 OXIDATION OF nrnaocmo'ns AND waxesAdolf v. Frledolshelm, Ludwinhafen-on-the- Rhine, and Martin Luther,-Mannheim, Germany, assignors to I. G. FarbenindustrieAktiengesellschaft, Frankfort on the Main,

Germany No Drawing. Application March 20, 1931, Serial No. 524,210. InGermany April 5, 1930 6 Claims. (01. 260-116) The present inventionrelates to improvements in the oxidation of hydrocarbons and waxes.

It has already been proposed to carry out the destructive oxidation ofdimculty volatile, from solid to liquid, non-aromatic hydrocarbons,hydrocarbon mixtures and waxes, with oxygen, air

'or other gaseous mixtures containing free oxygen,

in such a way that, in order to avoid undesirable by-products, theoxidation is interrupted after the conversion of a part of the initialmaterial employed or after reaching an acid value of 40, the unattackedhydrocarbons being subjected to oxidation again after the separation ofthe oxidized constituents and if desired after mixing with fresh initialmaterial. In this manner however only a small amount of the initialmaterials is converted into oxidation products at a time, so that thecomplete conversion of the initial material employed requires longperiods of time and a series of operations.

We have now found that colorless products containing only very smallamounts of hydroxy carboxylic acids and lactones are obtained in a considerably shorter time and in far greater yields when the destructiveoxidation of difficultly volatile, from solid to liquid non-aromatichydrocarbons containing at least 8 carbon atoms, hydrocarbon mixturesand Waxes is carried out in the presence of catalysts and is proceededwith until the products show an acid value above 40 but is interruptedas soon as an acid value between 80 and 120 is attained. Contrary toexpectation up to about '70 per cent and more of the initial materialsemployed are thus oxidized in one operation without a formation ofundesirable byproducts such as resin or decomposition products, coloredconstituents and the like, owing to the acceleration of the reaction bythe catalyst, and the formation of products of an injurious excessiveoxidation, colorations and the like are avoided which take placesuddenly in an increasing degree and which cannot be prevented even byincreasing the amount of catalyst employed.

The catalysts to be used according to the present invention are aboveall the compounds of the alkali metals and alkaline earth metals, andespecially those compounds which have an alka line reaction. It isespecially advantageous to carry out the oxidation of the hydrocarbonsand the like in the presence of catalysts consisting of compounds of thealkali metals, the oxidation at least being interrupted after theconversion of about 70 per cent of the initial material em-' ployed intoacids, usually corresponding to an acid value of from 80 to 120depending on the initial material. In this way the reaction products areobtained substantially in the form of free acids without any colorationand almost free from hydroxy carboxylic acids, lactones and esters, sothat the products are directly suitable for the further working up asfor example into soaps or emulsifying agents. The amounts in which thesecompounds of the alkali metals are employed are very small and will notexceed 1 per cent of the initial material; frequently one or a fewthousandths, calculated on the hydrocarbons to be oxidized aresuflicient so that no appreciable quantity of acids formed may combinewith an alkaline catalyst if such be employed. The catalysts areadvantageously added before or shortly after the beginning of theoxidation reaction. In the same way, other catalysts as for examplealkaline earth metal compounds such as calcium chloride and the like maybe employed. It is often advantageous to add, in addition to thesecatalysts, manganese or nickel salts, such as manganese naphthenate, orzinc stearate.

The present invention is suitable for the oxidation of liquid or solidnon-aromatic hydrocarbons containing at least 8 carbon atoms, orhydrocarbon mixtures, such as hard or soft paraffin wax,

ceresine, heavy or middle oils, naphthene hydrocarbons, such as paraflinoil, petroleum fractions, such as gas oil, synthetically preparedhydrocarbons, such as the products obtained by the destructivehydrogenation or low temperature carbonization of hard or soft coals,lignites, tars and the like. Similarly waxes, as for example Montan waxand the like; are suitable. The oxidation is preferably carried out attemperatures between about 120 and 180 C., it being preferable to workin aluminium vessels filled with aluminium fillers and in such a mannerthat excessive foaming occurs by the blast of oxidizing agents and thefillers reaching above the surface of the initial material. Othernon-corrodible materials as for example special steels may be employedinstead of aluminium.

The following examples will further illustrate the nature of thisinvention, but the invention is not restricted to these examples.

Example 1 kilogram of wax and per hour in order to start the reactionand are then oxidized for several hours at 140 C. The oxidation isinterrupted after about per cent of the hard paraflin w'ax employed havebeen converted into oxidation products containing oxygen which resultcan be ascertained by the acid value of the product or its specificgravity. The resulting reaction product has an acid value of 100 and asaponification value only slightly higher than 100; it contains 6 percent of hydroxy carboxylic acids and esters and is practicallycolorless. After separating the oxidized constituents by chemical orphysical means, as for example by saponification, extraction and thelike, the unattacked initial material is subjected to oxidation again,if desired in admixture with fresh initial material.

Example 2 500 kilograms of soft paraffin wax are blown with air at 150C. until an acid value of 10 is attained. 750 grams of potassiumcarbonate in the form of a saturated aqueous solution are then added andblowing air through the wax is continued at 150 C. until the product hasan acid value of 120, about 70 per cent of the initial material beingthen oxidized. The product is practically colorless and contains 7.5 percent of hydroxy carboxylic acids. After separating the unattackedinitial material the latter may be subjected to oxidation again.

What we claim is:-

1. In the oxidation, in the liquid state, of from solid to liquidnon-aromatic hydrocarbons containing at least 8 carbon atoms, mixturesof such hydrocarbons, and waxes, by blowing with a gas containing freeoxygen, the step which comprises adding up to 1 per cent by weight ofthe said nonaromatic hydrocarbons of an ionizable alkali metal compoundhaving an alkaline reaction and carrying on the oxidation until thereaction product has an acid value between 40 and 120.

2. A process as defined in claim 1, in which the catalyst is an alkalimetal compound having an alkaline reaction, and in which the oxidationis carried out at between 120 and 180 C.

3. A process as defined in claim 1, in which the catalyst is sodiumhydroxide.

4. A process as defined in claim 1, in which the catalyst is sodiumcarbonate.

5. A process as defined in claim 1, in which the oxidation is carried onuntil the reaction product has an acid value of about 80.

6. In the oxidation, in the liquid state, of parafiin by blowing withair at about 140 C., the step which comprises adding up to 1 per cent byweight of the paraffin of an ionizable alkali metal compound having analkaline reaction and carrying on the oxidation until the reactionproduct has an acid value of about 100.

ADOLF v. FRIEDOLSHEIM. MARTIN LUTHER.

